The young Los Angeles Lakers matured on Thursday night.

With four-time MVP LeBron James still sidelined by a left groin strain, Kyle Kuzma scored 32 points to help the Lakers beat the Oklahoma City Thunder 138-128 in overtime.

James missed his 12th straight game, yet against a veteran team loaded with All-Star talent, the Lakers rolled to a 16-6 advantage in the extra period.

“That was a really nice, big win for our group,” Lakers coach Luke Walton said. “We got contributions from everybody. This is a really hard place to win at. It’s a playoff team. For our guys to keep coming in and different people making plays — it’s how we have to compete.”

Ivica Zubac scored a career-high 26 points and Lonzo Ball added 18 points and 10 assists for the Lakers, who improved to 5-7 without their injured star.

Paul George scored 27 points and Terrance Ferguson added 21 for Oklahoma City. Russell Westbrook had 26 points, 13 assists and nine rebounds but shot just 7 of 30.

The Thunder lost despite making a franchise-record 21 3-pointers and leading by 17 in the first half. They have dropped five of six.

Westbrook missed two layups in the final minute but was fouled by Ball on a 3-pointer with 2.9 seconds remaining and the Lakers up 122-119. Westbrook, a 64 percent free throw shooter, made all three foul shots to tie the score. Kuzma missed a 3 at the buzzer, and the game went to overtime.

NBA crew chief Tom Washington acknowledged that Westbrook should never have been awarded free throws.

“Upon being able to see the review of the play, we realized that the illegal contact happened prior to his upward motion, so it should have been a side-out,” Washington said.

Ball took responsibility for the situation.

“It’s my fault that he hit the free throws,” he said. “Maybe I should have fouled him earlier. But I had to wash it off.”

Ball bounced back with five points, two rebounds and an assist in overtime. Walton was impressed with his second-year point guard’s overall effort, especially late in the game.

“For him to do that against Westbrook — I’m sure a player he watched growing up as one of the great point guards in our league — not only to score those points, but a couple of big assists to Zu coming down the lane, a big-time rebound. He can do a little bit of everything,” Walton said.